Mineral dust is annually emitted in large amounts into the troposphere and transported over transcontinental distances. Different interactions between dust particles and atmospheric trace gases can take place affecting, for instance, atmosphere’s oxidative capacity, the global radiation budget, and dust cloud condensation activity. Concomitantly, dicarboxylic acids (DCA) are a significant fraction of organic aerosols, and have been identified by field studies adsorbed on dust particles. The presence of low vapor pressure acids on the surface of dust creates an organic coating that, subsequently, can undergo heterogeneous chemical reactions enriching dust surface with oxygenated and polar organics. Therefore, we investigated the reaction pathways of glutaric and adipic acids on Arizona test dust (ATD) particles upon UV-A light irradiation. ATD contains 2-5% of Fe2O3 and 0.5-1% of TiO2, both recognized semiconductors that can lead to photocatalytic oxidation of organic compounds. The gas-phase composition was monitored online by a Proton Transfer Reaction Mass Spectrometer, and surface sorbed products were extracted from the dust and analyzed by Ultra-High-Performance Liquid Chromatography coupled to an Electrospray Ionization Mass Spectrometer. Our results show that irradiation turns this system from non-reactive to very reactive, leading to the production of various products, such as monocarboxylic acids, aldehydes, etc. in the gas-phase. The analysis of the dust extracts indicated the appearance of shorter chain DCA and other highly oxygenated products. We propose mechanistic insights, presenting how light could trigger new particle-phase chemistry and the atmospheric implications of such reactions on the surface of mineral aerosols.